Potentially optimize some GrGLEffects for known input color values

src/effects/gradients/SkTwoPointConicalGradient.cpp

Index: src/effects/gradients/SkTwoPointConicalGradient.cpp
diff --git a/src/effects/gradients/SkTwoPointConicalGradient.cpp b/src/effects/gradients/SkTwoPointConicalGradient.cpp
index 94eb72f5a08c730ea20d77fe75bc6f32150b2f21..1fd8c5272705dccbab76429c004fa49fea59903b 100644
--- a/src/effects/gradients/SkTwoPointConicalGradient.cpp
+++ b/src/effects/gradients/SkTwoPointConicalGradient.cpp
@@ -346,7 +346,7 @@ public:
                           const GrDrawEffect&,
                           EffectKey,
                           const char* outputColor,
-                          const char* inputColor,
+                          const GrGLSLExpr4& inputColor,
                           const TransformedCoordsArray&,
                           const TextureSamplerArray&) SK_OVERRIDE;
     virtual void setData(const GrGLUniformManager&, const GrDrawEffect&) SK_OVERRIDE;
@@ -501,7 +501,7 @@ void GrGLConical2Gradient::emitCode(GrGLShaderBuilder* builder,
                                     const GrDrawEffect&,
                                     EffectKey key,
                                     const char* outputColor,
-                                    const char* inputColor,
+                                    const GrGLSLExpr4& inputColor,
                                     const TransformedCoordsArray& coords,
                                     const TextureSamplerArray& samplers) {
     this->emitUniforms(builder, key);